`terraform show -json <planfile>` crashed when plan contains `ephemeral` block

[lonegunmanb]

Terraform Version

v1.13.4

Terraform Configuration Files

Any plan file contains ephemeral resource

Debug Output

I have plan file that creates ephemeral resources and when I executed terraform show -json planfile, it crashed with the following error message:

!!!!!!!!!!!!!!!!!!!!!!!!!!! TERRAFORM CRASH !!!!!!!!!!!!!!!!!!!!!!!!!!!!

Terraform crashed! This is always indicative of a bug within Terraform.
Please report the crash with Terraform[1] so that we can fix this.

When reporting bugs, please include your terraform version, the stack trace
shown below, and any additional information which may help replicate the issue.

[1]: https://github.com/hashicorp/terraform/issues

!!!!!!!!!!!!!!!!!!!!!!!!!!! TERRAFORM CRASH !!!!!!!!!!!!!!!!!!!!!!!!!!!!

panic: unsupported resource mode 69
goroutine 1 [running]:
runtime/debug.Stack()
        runtime/debug/stack.go:26 +0x5e
github.com/hashicorp/terraform/internal/logging.PanicHandler()
        github.com/hashicorp/terraform/internal/logging/panic.go:84 +0x16a
panic({0x34fe320?, 0xc001e3b400?})
        runtime/panic.go:792 +0x132
github.com/hashicorp/terraform/internal/command/jsonchecks.makeStaticObjectAddr({0x44a0468, 0xc0005d5440})
        github.com/hashicorp/terraform/internal/command/jsonchecks/objects.go:33 +0x925
github.com/hashicorp/terraform/internal/command/jsonchecks.MarshalCheckStates(0xc000724218)
        github.com/hashicorp/terraform/internal/command/jsonchecks/checks.go:51 +0x267
github.com/hashicorp/terraform/internal/command/jsonplan.Marshal(0xc0008856c0, 0xc0007e64e0, 0xc0008f06c0, 0xc000b0dbd0)
        github.com/hashicorp/terraform/internal/command/jsonplan/plan.go:317 +0x45f
github.com/hashicorp/terraform/internal/command/views.(*ShowJSON).Display(0xc000724020, 0x0?, 0x0?, 0xc002045988?, 0x0?, 0x1800000000000000?)
        github.com/hashicorp/terraform/internal/command/views/show.go:143 +0xfa
github.com/hashicorp/terraform/internal/command.(*ShowCommand).Run(0xc000582700, {0xc000070160, 0x2, 0x2})
        github.com/hashicorp/terraform/internal/command/show.go:86 +0x543
github.com/hashicorp/cli.(*CLI).Run(0xc0005d2280)
        github.com/hashicorp/cli@v1.1.7/cli.go:265 +0x4de
main.realMain()
        github.com/hashicorp/terraform/main.go:339 +0x1deb
main.main()
        github.com/hashicorp/terraform/main.go:64 +0x13

I have checked the source code:

ret["kind"] = "resource"
		switch addr.Resource.Mode {
		case addrs.ManagedResourceMode:
			ret["mode"] = "managed"
		case addrs.DataResourceMode:
			ret["mode"] = "data"
		default:
			panic(fmt.Sprintf("unsupported resource mode %#v", addr.Resource.Mode))
		}

Looks like we need add logic for ephemeral block?

Expected Behavior

No panic

Actual Behavior

Panic, crashed

Steps to Reproduce

terraform plan -out=file to create a plan with ephemeral in your TF config, then terraform show -json <plan>

Additional Context

No response

References

No response

Generative AI / LLM assisted development?

No response

[jbardin]

Thanks for filing the issue @lonegunmanb!

I'm assuming that given this error, you have a precondition or postcondition within an ephemeral block?

[lonegunmanb]

Thanks @jbardin for the reply, that's affirmative.

I've tried to remove precondition and it worked.

Please feel free to close this one, or maybe you'd like to keep it open until a pr fixed the panic? Both work for me, and again, thank you so much for the help! Have a nice day!

[Kim-Yukyung]

Hello, @jbardin

I believe I may be able to help address this issue. It appears that EphemeralResourceMode is not currently handled in internal/command/jsonchecks/objects.go within the switch statement.

I’m considering adding support for ephemeral resources, for example

case addrs.EphemeralResourceMode:
    ret["mode"] = "ephemeral"

If this approach looks reasonable, I would be happy to open a PR for the fix. Please let me know your thoughts.

Thank you!